Disease Information

Chronic Fatigue Syndrome (CFS)

Chronic fatigue syndrome, or CFS, is a devastating and complex disorder characterized by overwhelming fatigue that is not improved by bed rest and that may be worsened by physical or mental activity. People with CFS most often function at a significantly lower level of activity than they were capable of before the onset of illness.

In addition to these key defining characteristics, patients report various nonspecific symptoms, including weakness, muscle pain, impaired memory and/or mental concentration, insomnia, and post-exertional fatigue lasting more than 24 hours. In some cases, CFS can persist for years.

The cause or causes of CFS have not been identified and no specific diagnostic tests are available. Moreover, since many illnesses have incapacitating fatigue as a symptom, care must be taken to exclude other known and often treatable conditions before a diagnosis of CFS is made.

Therefore, in order to be diagnosed with chronic fatigue syndrome, a patient must satisfy two criteria:

  1. Have severe chronic fatigue for at least 6 months or longer that is not relieved by rest and not due to medical or psychiatric conditions associated with fatigue as excluded by clinical diagnosis; and
  2. Concurrently have four or more of the following symptoms:
    • self-reported impairment in short-term memory or concentration severe enough to cause substantial reduction in previous levels of occupational, educational, social, or personal activities
    • sore throat that's frequent or recurring
    • tender cervical or axillary lymph nodes
    • muscle pain
    • multi-joint pain without swelling or redness
    • headaches of a new type, pattern, or severity
    • unrefreshing sleep and
    • post-exertional malaise (extreme, prolonged exhaustion and sickness following physical or mental activity) lasting more than 24 hours.

The fatigue and impaired memory or concentration must have impaired normal daily activities, along with other symptoms that must have persisted or recurred during 6 or more consecutive months of illness and must not have predated the fatigue.

Causes of CFS

The cause or causes of CFS remain unknown, despite a vigorous search. While a single cause for CFS may yet be identified, another possibility is that CFS represents a common endpoint of disease resulting from multiple sudden causes. Some of the possible causes of CFS might be due to infectious agents, immunological dysfunction, stress activating the hypothalamic-pituitary adrenal (HPA) axis, neutrally mediated hypo tension, and/or nutritional deficiency.

Symptoms of CFS

The primary symptoms of CFS are severe fatigue, weakening that is not improved by bed rest and may be worsened with physical or mental activity. It is an all-encompassing fatigue that results in dramatic decline in both activity level and stamina.

The fatigue of CFS is accompanied by characteristic symptoms lasting at least 6 months. These symptoms include:

The symptoms listed above are the symptoms used to diagnose this illness. However, many CFS patients may experience other symptoms, including irritable bowel, depression or psychological problems, chills and night sweats, visual disturbances, allergies or sensitivities to foods, odors, chemicals, medications, or noise, brain fog, difficulty maintaining upright position, dizziness, balance problems or fainting.

Diagnosis of CFS

Because there is no blood test, brain scan or other lab test to diagnose CFS, it is a diagnosis of exclusion. A health care professional will first take a detailed patient history, then a thorough physical and mental status examination. Next, a series of laboratory screening tests will be ordered to help identify or rule out other possible causes of symptoms. There may also be additional tests to follow up on results of the initial screening tests. A diagnosis of insufficient fatigue could be made if a patient has been fatigued for 6 months or more, but does not meet the symptom criteria for CFS.

A clinician should consider a diagnosis of CFS if these two criteria are met:

  1. Unexplained, persistent fatigue that's not due to ongoing exertion, isn't substantially relieved by rest, is of new onset (not lifelong) and results in a significant reduction in previous levels of activity.
  2. Four or more of the following symptoms are present for six months or more:
    • Impaired memory or concentration
    • Post-exertional malaise (extreme, prolonged exhaustion and sickness following physical or mental activity)
    • Unrefreshing sleep
    • Muscle pain
    • Multi joint pain without swelling or redness
    • Headaches of a new type or severity
    • Sore throat that's frequent or recurring
    • Tender cervical or axillary lymph nodes

Treatment of CFS

Managing chronic fatigue syndrome can be as complex as the illness itself. There is no cure yet, no prescription drugs have been developed specifically for CFS, and symptoms vary considerably over time. These factors complicate the treatment picture, which require patients and doctors to always monitor and change treatment strategies.

One key to managing CFS is each patient needs to work with a team of doctors and other health care practitioners, which might include mental health professionals, rehabilitation specialist, and physical or exercise therapists, to create an individualized treatment program. This program should be based on a combination of therapies that address coping techniques, symptoms and activity management.



Stroke is the third leading cause of death in the United States. About 137,000 Americans die of stroke every year.1

A stroke, sometimes called a brain attack, occurs when a clot blocks the blood supply to the brain or when a blood vessel in the brain bursts. You can greatly reduce your risk for stroke through lifestyle changes and, in some cases, medication.

Stroke can cause death or significant disability, such as paralysis, speech difficulties, and emotional problems. Some new treatments can reduce stroke damage if patients get medical care soon after symptoms begin. When a stroke happens, it is important to recognize the symptoms, call 9-1-1 right away, and get to a hospital quickly.

What is stroke?

A stroke, sometimes called a brain attack, occurs when the blood supply to part of the brain is blocked or when a blood vessel in the brain bursts. In either case, parts of the brain become damaged or die.

There are two types of stroke. An ischemic stroke occurs when blood clots or other particles block the blood vessels to the brain. Fatty deposits called plaque can also cause blockages by building up in the blood vessels.

The second type, hemorrhagic stroke, occurs when a blood vessel bursts in the brain. Blood accumulates and compresses the surrounding brain tissue.

What are the symptoms of stroke?

Major signs of stroke include:

What should you do if you think someone is having a stroke?

If you think you or someone else is having a stroke, call 9–1–1 immediately.

Why do you need to act fast?

Getting fast medical treatment lowers your risk of disability or even death. That’s why it’s important to recognize the symptoms—and to get help right away.

What are the risk factors for stroke?

Several conditions and certain lifestyle choices can put people at higher risk for stroke. The most important risk factors are:

Everyone can take steps to lower the risk for stroke.

What can you do to reduce your risk?

You can take several steps to reduce your risk for stroke—

Talk with your doctor about the best ways to lower your risk for stroke.

How many Americans die from stroke?

Stroke kills around 137,000 people a year in the United States. It is the third leading cause of death.1 Stroke is also a leading cause of serious long-term disability.

How much does stroke cost the United States?

The American Heart Association estimates that stroke will cost the country about $68.9 billion in 2009. This total includes health care services, medications, and lost productivity due to illness or death.

What does CDC do to address stroke?

CDC has several initiatives to help people prevent and control stroke. CDC funds state health departments to develop interventions aimed at preventing stroke and controlling its risk factors. CDC also funds states to track stroke data through the Paul Coverdell National Acute Stroke Registry to improve hospital care. In addition, CDC supports a national plan with targeted recommendations and specific action steps to reduce heart disease and stroke across the country.

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